Question about 2001 Subaru Forester

Open Question

Very rough idle

My Forester starts and idles @ up to 2,000RPM (!) for a few moments. As it idles down, the idle gets very rough. The piston-slap that was there before (I think), seems more pronounced as well. ODO reads about 144,000 miles. 2.5L SOHC w/ an auto trans *newer plugs, wires, fuel filer *new head gaskets, timing belt, idler pullys, TB tensioner, water pump, upper/lower radiator hoses, coolant, thermostat, accy belts *professionally cleaned and milled heads with adjusted rockers and ground valves I'm about at wits end. (As well as the end of my checking account!) The dealer did a diagnostics check and told me about the knock sensor and the pre-cat O2 sensor, which was good! I really doubt that the O2 sensor is going to do this. I cannot find any hoses that I missed after reassembling the engine. Anyone have any idea's?

Posted by on

  • NIMBY
    NIMBY Feb 15, 2014

    I let it sit for a while and drove another car. That obviously cured nothing.

  • NIMBY
    NIMBY Feb 15, 2014

    I took it to a small private guy, and he let me know that doing the head job was good. However, making sure all the gasket material is off of the intake manefold helps the whole sealing process more. Huh, who'd have guessed? Runs great now, except for the piston slap.

×

Ad

2 Suggested Answers

6ya6ya
  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi,
a 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
New users get to try the service completely Free afterwhich it costs $6 per call and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
Goodluck!

Posted on Jan 02, 2017

Ad
  • 111 Answers

SOURCE: My 1998 subaru forester keeps

Subarus tend to block their radiators. Often there is only 10% or less flow. The radiator needs to be taken out and have a radiator shop strip and rod out the core tubes or fit a new or recored radiator.

Posted on May 02, 2011

Ad

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

Rough idle in cold weather


Is there a check engine light on?

Nov 29, 2012 | 2005 Subaru Forester 2.5

1 Answer

Subaru forester 2005 has rough idle...


Spark Plugs --change every 3 years?
Front O2 Sensors-replaced at 100,000 miles?
MAF Sensor-cleaned?
Egr System works as it should?
No cylinder misfires?
No Vacuum Leaks anywhere?
No stored codes?

Shall I keep going?

You have to work on all vehicles at least twice a year
& look for problems

Alternator has no ac leakiage
Fuel filter new
Fuel pressure good
Air filter?
Throttle Plate doesn't stick?

Nov 29, 2012 | 2005 Subaru Forester

1 Answer

It has rough idle when you first start it then straightens out after warming up


sounds like low compression at start up do to piston slap and not alowing car to warm up over the years before driving off. 3.1, 3.4, 3.5 motor pistons are exact size at operating temp there for cold temps at start up cause the pistons to slap the cylinder wall.. Gm engineers did this to reduce operating temp while driving by lowering friction in the cylinder. problem is most people these days start there cars and take off down the road..my suggesting would be to check piston compersion at operating temp and see if it meets spefications for ur mottor before replacing any other parts...

Aug 16, 2012 | 1995 Oldsmobile Cutlass Supreme

1 Answer

When I start the car it stays at 2000rpm for a few moments then drops down. I'll drive for a few minutes then put it in park and it revs up and down.


idle air control valve is bad replace it. at start up choke control runs till warm up while driving throttle opening controls engine at idle ,the idle air control valve.

Aug 01, 2012 | 2005 Chevrolet Aveo

1 Answer

I have a 1997 2.5 jeep wrangler.when you first start the engine it runs and sounds fine, then after about 20 seconds it begins to have a knocking sound only at idle. when you press the gas you cant hear...


It may be piston slap. This is caused by either engine wear with the piston bores being too large for the pistons, or by poor manufacturing tolerances, or a combination of both.

To test for this, start the engine up first thing in the morning and run it for about thirty seconds while you listen carefully and memorise the sound and intensity. Turn the engine off quickly, remove the spark plugs and put two squirts of motor oil into each cylinder. Reinstall the plugs, start the engine up again and listen. If you have piston slap the noise will have been greatly reduced or even eliminated for about thirty seconds seconds and then returns.

The fix is to rebuild or replace the engine, but if it works just fine then don't worry. Many slappy engines keep going for tens of thousands more mile. The fact that your knocking is only at idle suggests your crankshaft is not to blame.

Sep 26, 2010 | 1997 Jeep Wrangler

1 Answer

ROUGH IDLE


Did you replace the plugs with the same plugs (Manufacturer) as the plugs you had in there. Some cars are very picky with plugs. ie: some Japanese cars will only run well with NGK Spark Plugs. Try to use only what Subaru recommends in your engine for the best performance.

Jun 06, 2010 | 1999 Subaru Forester

1 Answer

Cold start-extremely rough idle-Shakes,smell fuel


Black smoke means buring rich. Have the vehicle's ECU scanned for codes and do the repair the codes describe. I'm gonna take a stab in the dark and say Mass Air Flow Sensor.(MAF)

May 07, 2010 | 2003 Subaru Forester

1 Answer

Ford Taurus: rough idle in drive and reverse


it could be that the tick over is two slow in brive,,,
set it up to tickover at 850,,950 rpm (in drive)
or it could be a gear box fult like the drive plate has a crack in it,,,letting the torque converter slap about,,,
chech tick over first,,, bont adjust tick over in gear unless the brakes are held hard on,,,

Oct 31, 2009 | Ford Taurus Cars & Trucks

1 Answer

Erratic idoling when warm


sounds like the air idle valve , if you can get hold of valve to test, try this find valve on inlet manifold and pull hose off going to throttle body,reconect hose to new valve so valves are i line to each other, start car and let it idle for a few moments till the fast idle slows down, then disconnect the wirering goint to the original aiv and connect to the new one , hopefully the original one would have been diconnected in the open position , reconnect wirering to the new valve and turn engine off. disconnect battery for 20 seconds . recon battery and turn ignition on, pump gas pedel 5 times to reset . start engine and let it idle for a few moments ,then try to turn steering wheel , engine speed should rise slightly due to load from power steering pump and then settle back down 875 1075 rpm.this is what the air idle valve should do. if it doesen't look at wiring goig to aiv might have scuffed through.

Aug 09, 2009 | 2002 Land Rover Freelander

2 Answers

Engine make Knocking noise when cold


I have the same problem on my 2.0L 2001 Legacy auto. It began about 1000 miles ago. It has now done 84k. From my online searches this is most probably 'piston slap', and is not serious. To save weight Subaru shaved down the skirts on the pistons. With normal engine wear the pistons will at some point rattle against the cylinders until the engine is heated up and the pistons expand. The rattling should go away after a few minutes. If it persists say 10-15 minutes, it may be another problem.

Feb 06, 2009 | 1998 Subaru Forester

Not finding what you are looking for?
2001 Subaru Forester Logo

Related Topics:

27 people viewed this question

Ask a Question

Usually answered in minutes!

Top Subaru Experts

yadayada
yadayada

Level 3 Expert

76630 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22219 Answers

Jeff Turcotte
Jeff Turcotte

Level 3 Expert

8514 Answers

Are you a Subaru Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...